The disclosure relates generally to anthrapyridone compositions and methods for their preparation. The anthrapyridone compositions disclosed herein are useful as colorants in resin compositions.
Colored resin compositions are generally prepared by incorporating the colorant material in the resin matrix in a processing step using techniques, such as extrusion or molding. The method of incorporating the colorant material depends upon, among other conditions, the nature of the resin matrix. For resins that require high processing temperatures of about 350° C. or higher, it is necessary that the colorant material be thermally stable at these higher processing temperatures. Examples of resins that require processing temperatures of about 350° C. or higher include high heat polycarbonates, which have glass transition temperatures greater than that of bisphenol A homopolycarbonate, and polyetherimides, such as ULTEM™. Another issue with using colorants under such high temperature processing conditions is that the processed resins sometimes exhibit a color which is different from that expected based on the color of the colorant material used. This color shift generally occurs as a result of the thermal instability of the colorant material.
Therefore, there is a need for thermally stable colorant materials that are resistant to degradation and color shift when processed with resins at elevated temperatures. Such thermally stable colorants are preferably weatherable. That is, the colorant withstands degradation brought about by environmental factors, such as atmospheric air, moisture, and sunlight.